1. Field of the Invention
The present invention relates to a thermal insulation and a method of producing the same, and more particularly, to an improvement in the strength of a thermal insulation.
2. Description of the Related Art
Conventionally, as thermal insulations having low thermal conductivity and being excellent in thermal insulating performance, there have been known ones which are obtained by mixing silica fine particles as a material having a low thermal conductivity, an inorganic fiber, and a binder, and then subjecting the mixture to press forming, followed by machining (for example, JP 11-513349 A and JP 11-514959 A).
However, the above-mentioned conventional technologies have involved a problem in that use of the binder requires, for example, removal of oil, which causes reduction in the strength of the thermal insulations. In addition, the use of the binder increases environmental impact. As described above, there has been a problem in that the removal of oil or the like involves increases in the number of steps and required time and energy when the binder is used.
In contrast, it is also possible to enhance the strength of a thermal insulation by increasing the density of the thermal insulation through the adjustment of pressing pressure without use of a binder. However, this case has involved a problem, for example, in that the thermal insulating performance of the thermal insulation lowers because the increase in the density of the thermal insulation involves an increase in the solid heat transfer.